A fuse element may be used in an integrated circuit such as, for example, a one time programmable (OTP) memory. An example of a traditional fuse element is a polysilicon fuse. Polysilicon fuse elements may be “blown” or “programmed” by passing high current through the element until it encounters a thermal breakdown. A blown fuse may exhibit a resistivity that is, for example, 3-10 times higher than a “non-blown” or “unprogrammed” fuse element.
Traditional fuse elements like the polysilicon fuse element may require a high programming current (e.g., 100 mA). As a result, devices such as a vertical drain NMOS (VDNMOS) may be necessary to protect sensitive devices that may be damaged by the large programming current. Such protective devices may be large and result in a fuse cell that occupies a large silicon area (e.g., 1000 m2). In addition, blowing a polysilicon fuse may be unreliable because it is not cumulative. In other words, if the fuse does not blow correctly, it cannot be further blown by reapplying the programming current or some variation of the programming current. As a result, a certain redundancy may be required to compensate for the fuses that do not initially blow correctly. Furthermore, the resistance differential between a blown and a non-blown polysilicon fuse is small. This may cause difficulties when designing a sensing scheme that can operate reliably despite process and temperature variations.